Southwestern Puerto Rico out 10NM Marine Forecast
| Today...East Winds 5 To 10 Knots, Becoming Southeast 10 To 15 Knots With Gusts Up To 20 Knots Late This Morning And Afternoon. Seas Around 2 Feet. Wave Detail: Southeast 2 Feet At 4 Seconds. Isolated Showers This Morning, Then Scattered Showers With Isolated Thunderstorms This Afternoon. |
| Tonight...East Winds 5 To 10 Knots, Increasing To 10 To 15 Knots With Gusts Up To 20 Knots After Midnight. Seas Around 2 Feet. Wave Detail: Southeast 2 Feet At 4 Seconds. |
| Thursday...Southeast Winds 10 To 15 Knots With Gusts Up To 25 Knots. Seas 2 To 3 Feet. Wave Detail: East 2 Feet At 5 Seconds. Scattered Showers In The Afternoon. |
| Thursday Night...East Winds 15 To 20 Knots, Diminishing To 10 To 15 Knots After Midnight. Seas 2 To 3 Feet. Wave Detail: Southeast 3 Feet At 5 Seconds. |
| Friday...East Winds 5 To 10 Knots, Becoming Southeast In The Afternoon. Seas 2 To 3 Feet. Wave Detail: Southeast 2 Feet At 6 Seconds. |
| Friday Night...East Winds 5 To 10 Knots. Seas 2 To 3 Feet. Wave Detail: Southeast 2 Feet At 6 Seconds. |
| Saturday...East Winds 10 To 15 Knots. Seas 2 To 3 Feet. Scattered Showers In The Afternoon. |
| Saturday Night...East Winds 10 To 15 Knots, Diminishing To 5 To 10 Knots After Midnight. Seas 2 To 3 Feet. |
| Sunday...East Winds 10 To 15 Knots. Seas 2 To 3 Feet. |
| Sunday Night...East Winds 10 To 15 Knots, Diminishing To 5 To 10 Knots After Midnight. Seas 2 To 3 Feet. Winds And Seas Higher In And Near Thunderstorms. |
| Area Forecast Discussion National Weather Service San Juan PR 227am AST Wednesday August 19 2026 .Short Term(Today through Friday)... Issued at 209am AST Wednesday August 19 2026 A tropical wave (former Invest 94L), currently with its axis located over Puerto Rico, will continue to move westward across the region overnight and into the morning hours. An increase in shower activity is already visible on Doppler radar and satellite imagery, with isolated to scattered showers primarily affecting eastern and northern Puerto Rico, as well as the surrounding regional waters. No significant rainfall accumulations have been reported so far. As the wave moves farther west, abundant tropical moisture will continue to filter into the region, increasing precipitable water (PWAT) values up to 2.25 inches. This wave is interacting with an upper-level trough to the northeast, increasing atmospheric instability aloft. This instability will be further supported by cooler mid-level temperatures (-7°C at 500 mb), elevating the potential for thunderstorms across the area. Current weather patterns and the latest model guidance favor periods of moderate to heavy showers and isolated thunderstorms across eastern Puerto Rico and portions of the U.S. Virgin Islands during the morning. As the day progresses, this activity will shift toward central, western, and northwestern Puerto Rico during the afternoon. Additional shower and isolated thunderstorm development is expected across the San Juan metropolitan area due to streamer activity forming downwind of El Yunque. Consequently, there is an elevated flooding risk across western and northwestern Puerto Rico, alongside a limited risk across the eastern interior and southeastern portions of Puerto Rico and the U.S. Virgin Islands. The moisture field from this tropical wave is expected to exit the area by this evening into Thursday, replaced by a drier airmass accompanied by low-to-moderate concentrations of Saharan dust. PWAT (Precipitable Water) values will drop rapidly to well-below-normal levels around 1.25 inches, persisting through at least Friday. Meanwhile, a surface high-pressure system over the central Atlantic will maintain breezy east-southeastern winds through the end of the week. Cloud cover and rainfall associated with the tropical wave may bring temporary relief from the recent warm spell. However, high temperatures and heat indices exceeding 100°F remain possible across coastal and urban areas during the morning, depending on the extent of cloud cover. Once the wave passes, an elevated to significant heat risk is projected to return on Thursday and continue through the rest of the week. Residents and visitors are encouraged to monitor updating weather reports, take precautions against the heat, and stay hydrated. .Long Term(Saturday through Wednesday)... Issued at 209am AST Wednesday August 19 2026 A generally dry and breezy pattern is expected through the long-term period. Very dry mid-level conditions, warmer-than-normal temperatures aloft, and intermittent Saharan dust should limit the depth and coverage of convection, although patches of low-level moisture and a tropical wave crossing early next week may still support brief passing showers and localized afternoon development. No significant rainfall hazards are anticipated at this time. Heat will remain the primary hazard, with elevated to locally significant heat risk possible where sufficient sunshine occurs. Persistent breezy winds, dry conditions, and limited wetting rainfall may also continue to support elevated fire weather concerns, particularly across the driest areas. Overall, hazards should remain focused on heat and fire weather rather than rainfall through the period. Marine Issued at 209am AST Wednesday August 19 2026 Light to moderate easterly trade winds will continue to prevail across the region over the next few days. Seas are expected to remain below small craft advisory criteria through the end of the week. Today, a weak tropical wave will continue to bring showers and thunderstorms across portions of the regional waters. This will elevate localized lightning hazards and bring gusty winds. From Thursday onward, expect hazy skies across the northeastern Caribbean due to moderate concentrations of Saharan dust. Beach Forecast Issued at 209am AST Wednesday August 19 2026 There is a low risk of rip currents today across all beaches of Puerto Rico and the U.S. Virgin Islands. However, the lightning potential will increase due to thunderstorm activity associated with the arrival of a tropical wave. Through the rest of the week, a low to moderate risk of rip currents is expected to prevail across all islands as winds and seas ease across most coastal waters. However, remember that even when the risk is low, life-threatening rip currents can occur near groins, jetties, reefs, and piers. Moderate concentrations of Saharan dust will promote hazy skies on Thursday and Friday. .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. |
San Juan Radar
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